textile design & innovations

Weaving Preparation. Part I: An Introduction

To produce woven fabrics, the produced yarns should go through certain processes to be prepared to use as ‘Warp’ yarns and as ‘Weft’. Woven fabrics consist of two sets of yarns, Warp and Weft, which are interlaced together at 90 degree angle. Warp are the yarns longwise the fabrics, weft are the yarns that go crosswise. The interlacing process takes place on the weaving machine, which will be discussed some where else. Figure (1), shows a general weaving steps of woven fabric from yarn to garments.

Figure (1): Manufacturing Steps of Woven Fabrics

Warp and Weft yarns go through different preparation, to sum up the stages figure (2) shows the steps for warp preparation and for weft preparation.

Figure (2): Warp and Weft preparation

For the winding process it will be discussed more in detail in a spinning content. It is used here in the weaving preparation stage in order to save money and waste.

Weft Preparation

Weft preparations are very short stages and it is only for looms. Meaning that for new weaving machines there is no need for any kind of preparation, the yarn packages are placed on the weft insertion creel directly as they are. For looms, the yarns need to be converted from packages to a spool or a quill, on which the weft yarn is wound. This quill will be inserted in a shuttle by which the weft will be spread cross the fabric.

Figure (3): The Loom Shuttle and the Quill

This stage can be done manually or on a special machines. Figure 4 below shows the hand wheel to wind the quills.

The most important thing when winding quills is to build a conical shape from base to top for smother unwinding inside the shuttle on the loom.

Figure (6): Quills Produced on Machines

Warp preparation

This stage is to prepare the warp yarns for the weaving machines and it consists of, warping (direct and indirect), Sizing (or Slashing) and then Tying in or Drawing in. In this part, Part I the introduction, we will introduce a simple definition to each stage with a simple explanation. Parts II to V will deal in detail with each stage separately. Part II: Direct Warping, Part III: Indirect Warping, Part IV: Slashing and Part V: Tying in and Drawing in. Part II: is under construction and hopefully will be uploaded in two weeks times.

Warping

This stage is to prepare the weaver’s beam to be place and set up on the weaving machine. In this stage a desirable length and number of warp yarns are arranged in the desired sequence and placed on a beam. Depending on how that is done and on the intermediate carrier used, there are two types of Warping;

Sectional Warping (Indirect Warping) In this Warping the yarn are being unwound from the packages to a conical drum at a certain width, length and density, then they yarns will be rewound to the weaver’s beam.

Direct Warping (Beam Warping) In this type, the yarn are being unwound form packages to a temporarily beams, at a certain length, number and density. Then these beam will be assembled in the slashing stage to produce the weaver’s beam.

More details about these two stages will be dealt with in Parts II and III.

Slashing It is an operation that is carried out on spun yarns that lack tenacity for weaving process and for filament yarns that have no twists. A film of thin starch is being applied on the surface of the yarns to give strength and smoothness to it to endure the tensions on the weaving machine. Slashing will be discussed in Part IV.

Drawing in Is the process warp yarns are being threaded through the drop wires, healds eyes and reed dents. Depending on the style, the threading sequence will differ.

Tying in In this stage, if the you still want to continue with the same pattern and warp yarn number and density, tying in is the process when a machine knot the old yarns on the weaving machine to the new warp yarns set on the new weaver’s beam. Drawing in and Tying in will be in details in Part V.